Abstract : Due to past operations, soils at some military installations have been contaminated with explosives. Past military operations have included production, testing, and disposal of explosive products. This report presents results of a study conducted at the Picatinny Arsenal, which was established in the 1800's. Production of explosives at the site has ceased, but as a result of the past activities, contaminants are migrating into the groundwater due to contaminant transport from the soils. Two technologies were evaluated for the treatment of groundwater contaminated with explosives: ultraviolet/chemical oxidation (UV/ChO) and granular activated carbon adsorption. This report presents the results of the UV/ChO study conducted to determine whether low levels of cyclotrimethylene-trinitramine (RDX) and cyclotetramethylene-tetranitramine (MHX) in the drinking water supply at the site could be treated to the required levels. The concentrations of RDX and HMX in the drinking water supply, sampled from well 410 at the site, are approximately 6 and 2 micrograms/L, respectively. In the 1980's, RDX and HMX were below health advisory levels. Health advisory levels were lowered in November 1988 by the U.S. Environmental Protection Agency (USEPA) to 2 and 400 micrograms/L for RDX and HMX, respectively. jg